Chromium plating apparatus



Oct. 25, 1932.

A. J. ZIMNlEWlCZ ET AL CHROMIUM PLATING APPARATUS Original Filed Jan. 25, 1930 3 Sheets-Sheet g/(iii; 17 6566, W M m Oct. 1932- A. J. ZIMNIEWICZ ET AL cnnomum PLATING APPARATUS Original Filed Jan. 25. 1930 3 Sheets-Sheet 2 a J Z'iizizz'ewwz. vi? 335?). W W

Oct. 1932- A. J. ZIMNHEWICZ ET AL 1,384,493

CHROMIUM PLAT ING APPARATUS Original Filed Jan. 25, 1930 3 Sheets-Sheet 3 .lution, as already suggested.

Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE ANTHONY J. ZIMNIEWICZ AND ARTHUR 1. CO1, 01 CHICAGO, ILLINOIS, ABSIGNORS 'IO MANZ BOTOGBAVURE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OI ILLINOIS CHBOMIUM PLATING APPARATUS Original application filed January 25, 1980, Serial No. 428,315. Divided andthis epplleatica filed December 24, 1930. Serial No. 504,614.

This invention relates to improvements in chromium plating apparatus.

This application is a division of our prior application bearing Serial No. 423,315 filed January 25, 1930, relating to the process broadly disclosed herein.

The principal object of the invention is-to provide an improved apparatus of the character described, particularly adapted for plating massive articles such as rotogravure printing rolls, although not limited to such use. A further object is to provide an improved construction for adjusting the apparatus to varying sizes of articles to be plated.

As v heretofore practiced, the chrominum plating process has been applied'to a wide variety of articles, but it has generally been;

considered essential to the successful operation of the process that the articles being plated should be maintained stationary in the plating solution, and that all agitation of the latter should be avoided during the depositing of metal therefrom. Thus, al-

though it has been the more or less common practice in the copper and other plating processes to move articles through the solution, and more specifically to rotate printing rolls at relatively high peripheral rates (in the order of at least 100 feet per minute and usually much higher) yet it has been heretofore considered that. such rotational movement' could not be used in the chromium plating process on account of the peculiar nature of the electroyltic :action of the chromium so- Welimi demonstrated, however, that under certain conditions, where the peripheral speed of the rolls is reduced to a considerably lower rate than-heretofore practiced in 'copper plating, and thus minimize agitation of the chromium solution, the chromium plating process can be carried out with muchgreater success, particularly 111 so far as uniformity of distribution of the metallic deposit, than is possible when the work is held stationary in the chromium solution, as here tofore.

Other features of the inventionwill appear from time to time as the following description proceeds.

T e invention may best be understood by reference to the accompanying drawings, in which Figure 1 is a side view of a plating tank tconstructed in accordance with our invenion.

Figure 2 is a plan view of the tank shown in Figure 1 but with the ventilating flues removed from the sides thereof.

Fi re 3 is an end view of the tank, shown in Figure 2.

Figure 4 is a section taken on line 44 of Figure 2, and including the ventilating flues.

Referring now to details shown in the embodiment of our invention, the plating tank is indicated generally at 10, and includes side walls 11, 12, end walls-13 and 14, and bottOIn 15. p

The tank is preferably of metal and suitably lined as with antimony lead for containing the chromium plating solution, such as chromium sulphate commonly used in the art.

Heating means, herein consisting of a steam pipe coil 16, extends into the bottom of the tank, as usual.

The work to be plated is illustrated in the drawings as consisting of a printing cylinder or roller 17 such as used in a rotogravure machine, which cylinder is provided with shaft 18 extending beyond opposite ends thereof. The work is suspended in the tank -19'19 suitably supported above the tank, as

for instance by brackets 21-21 are secured to a horizontal beam 22 or the like at some distance above the tank. The bus bars 19-49 are preferably formed of relatively heavy laminated copper strips which provide electrical connection direct to the printing cylinder when the latter issu'spended in the plating solution. In order to permit the bus bars to be removed from the solution when not in use, they are each preferably hinged at 23 to their respective overhead brackets 21 so as to permit the lower ends of the bars to be swung upwardly and maintained above the the printing cylinder.

, level of the solution, as for instance, by supporting said bars over the upper edges of the "tank.

' of the said vertical bus bars. Said braces are of course detached from said bus bars when the latter are swung upwardly out of the solution.

The arrangement shown in the drawings, is such that the top of the tank is left open to permit handling of the printing cylinder by means of an overhead crane of any usual form (not shown) both for lowering the cylinder into position on the hooks 20-20 within the tank and for lifting the cylinder out of the tank after the plating process is completed.

The electric circuit is completed through a pair of horizontally disposed bus bars 29-29 extending longitudinally of the tank in parallel relation and on opposite sides of the space in which the printing cylinderis disposed. These bus bars each have a plurality of lead anodes 30 suspended vertically therefrom a parallel relation, as clearly shown in Figures 1, 2 and 3. I

Means are provided for shifting or adjusting the bus bars 29-29 laterally with respect to each other so as tocontrol the horizontal distance between the lead anodes and In the form shown, said adjusting means for each of the bus bars consists of a pair of carriages 31-31 mounted on opposite ends of the tank and supporting the two ends of each of said bus bars by means of insulating blocks 32-32 of suitable construction. A spur gear 33 carried by each of said carriages engages racks 34-34 extending along the upper edge of the two ends of the tank. In the preferred form shown the two'spur gears 33-33 associated with one bus bar are connected by means of a rack shaft 35 extending the full length of the tank so as to rotate said gears 33-33 at uniform rates. The opposite bus bar 29 is provided with a similar rack shaft 35 for driving its gears 33-33 in unison. Said rack shafts are controlled by any suitable means, in the form shown. being provided with squaredends 36-36 which are adapted to be rotated by a detachable wrench or its equivalent.

By means of the laterally adiusted bus bars 29-29 just described, the position of the lead anodes 30-30 may be varied to accomrnndate the apparatus to printing cylinders of different sizes, and also to control the work- 'ing distance between the lead anodes and the work if desired.

peripheral speed of 20 feet The longitudinal bus bars 29-29 are suitably connected with a source of current sup- .ply as, for instance, the pair of bus bars posed shaft 42 extending through the end 13 1 of said tank. A pinion is disposed on the end of shaft 42. A sprocket 43 isdetachably mounted on the adjacent end of the cylinder shaft 18 and a chain 44 connects the said sprocket with the pinion 45.

In carrying out our invention, we find that with suitable gear reduction from the motor 39, it is possible to limit the peripheral speed of rotation of the printing cylinder 17 between 10 to 30 feet per minute, while best results are usually obtained at an approximate r minute. With the speed thus limited, we nd that the agitation of the chromium plating solution is kept at a minimum, while the chromium is deposited over the outer surface of the printing cylinder with much greater uniformity than is possible when the cylinder is kept stationary in the plating solution, as has heretofore been considered essential practice.

In Figures 1 and 4 we have also indicated. the arrangement of a pair of exhaust air ducts 46 at opposite sides of the tank, each arranged with a narrow opening 47 along the upper side edges of the tank so as to remove objectionable gases produced during the operation of the plating process.

The means for adjusting the lateral positions of anodes 30-30 at opposite sides of the work produces a ready and quick means for determining the proper spacing of such anodes from the work. Each set of anodes are moved by a single operation of its respective rack shaft 35.

Although we have shown and described one particular embodiment of our invention, it will be understood that we do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope ofour invention.

vWe claim as our invention:

1. In an apparatus of the character described. a tank adapted to contain a plating solution. an electric conductor extending therefrom into said solution, and means for bodily shifting said conductor and anodes 4 to various adjusted positions laterally of said tank consisting of a pair of carriages movably supporting said, conductor on opposite ends of said tank and rack and pinion means for moving said carriages.

2. In an apparatus of the character described, a tank adapted to contain a plating solution, an electric conductor extending longitudinally of the top of said tank and having a plurality of anodes depending therefrom into said solution, and means for bodily shifting said conductor and anodes to various adjusted positions laterally of said tank consisting of a pair of carriages movably supporting said conductor on opposite ends of said tank, and rack and pinion means including a common longitudinally disposed operating shaft for simultaneously shifting both of said carriages along said tank ends.

3. In an apparatus of the character described, a tank adapted to contain a plating solution, an electric conductor extending longitudinally of the top of said tank and having a plurality of anodes depending therefrom into said solution, and means for bodily shifting said conductor and anodes laterally of said tank consisting of a pair of carriages movably supporting said conductor on opposite ends of said tank, andmeans for simultaneously shifting both of said carriages along said tank ends, comprising means gearing each of said carriages to said tank ends, and a common shaft extending the length ofsaid tank for operating both of said gearing means at uniform rates.

4. In an apparatus of the character described, a tank open and unobstructed across the top and adapted to contain a plating solution, means supported above the top margins of said tank for suspending work in said tank comprising a current supply conductor to said work, means detachably connectible to said conductor and extending to one side of said tank for maintaining said conductor in spaced relation therefrom, and means supported on said tank to. one'side of said conductor for rotating said work in said solution.

5. In an apparatus of the character described, a tank open and unobstructed across the top and adapted to contain a plating solution, electric conductor means suspended from above the top margin of said tank and extending into the same to form'the sole 6. In an apparatus of the character described, a tank open and unobstructed across the top adapted to contain a plating solution, electric conductor means independently supported and suspended above the top margin ,5

of said tank, said conductor means having a flexible portion permitting it to depend 

